Japanese Patent Laying-Open No. 2011-78296 (PTD 1) discloses an inverter including four transistors and four diodes, and configured to convert a high voltage, a low voltage and an intermediate voltage into a three-level AC voltage. According to this inverter, among four diodes, each of two diodes performing a reverse recovery operation is formed of a wide band gap semiconductor, thereby reducing recovery loss. Also, each of two diodes not performing a reverse recovery operation is formed of a semiconductor other than such a wide band gap semiconductor, thereby reducing cost.